JPH0643821B2 - Fuel supply device for internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel supply device for an internal combustion engine, and more particularly to improvement of acceleration performance.

<Prior Art> The following is a conventional example of a fuel supply device for an internal combustion engine (see Japanese Utility Model Laid-Open No. 61-183440).

That is, the basic injection amount T _P = K × Q is calculated from the intake air flow rate Q detected by the air flow meter and the engine rotation speed N.
/ N (K is a constant) and various correction factors COEF mainly according to the water temperature, the air-fuel ratio feedback correction factor α, and the correction factor T _S due to the battery voltage are calculated, and then the fuel injection amount T _i = T _P Calculate × COEF × α + T _S.

Then, in synchronization with the engine rotation, an injection pulse signal having a pulse width corresponding to the fuel injection amount T _i is output to the fuel injection valve to supply fuel to the engine.

Further, during acceleration operation, an acceleration increase correction coefficient or an acceleration increase fuel injection amount is calculated from data mainly including the rate of change of the intake throttle opening, and the increase fuel injection amount is added to the fuel injection amount T _i . The engine output is increased by increasing the fuel acceleration.

The acceleration increase is also performed by interrupt injection that is performed by interrupting the injection pulse during acceleration during the normal injection pulse signal.

<Problems to be Solved by the Invention> However, in such a conventional fuel supply device, the basic injection amount T _P is calculated based on the detected intake air amount Q of the air flow meter provided upstream of the intake throttle valve. Therefore, there were the following problems during acceleration operation.

That is, since the air flow meter is provided upstream of the intake throttle valve, the air flow meter is introduced into the collector section downstream of the intake throttle valve even after the valve opening operation during acceleration of the intake throttle valve is completed as shown in FIG. The detected intake air flow rate or intake inertia component is additionally detected. Therefore, the detected intake air flow rate of the air flow meter greatly exceeds the intake air flow rate introduced into the engine as shown in FIG. Therefore, the basic injection amount T _P is calculated based on the detected intake air flow rate of the air flow meter.
When the (fuel injection amount) is calculated, this calculated amount greatly exceeds the required fuel amount of the engine, and as shown in FIG. 6, the air-fuel ratio becomes overrich and the CO and HC emissions increase, resulting in acceleration performance. Also, there is a problem that fuel efficiency is deteriorated. In addition, the load (for example, intake air flow rate, basic injection amount) at the time of calculating the fuel injection amount of the previous time and this time is always weighted and averaged by a constant weighting coefficient, and the fuel injection amount is calculated based on this value. is there. There is also a method in which the weighting coefficient is changed stepwise when a certain load is crossed during acceleration / deceleration.

However, with this type, although the amount of overshoot of the detected intake air flow rate can be suppressed, the fuel injection amount is suppressed even in the initial stage of acceleration operation, and over lean occurs in this initial stage, and acceleration performance cannot be sufficiently improved. Also, for those that change the weighting coefficient in steps, it is not possible to suppress the overshoot amount by acceleration etc. just before reaching a certain load, and overcharging due to overshoot in normal acceleration represented by 10 modes etc. Cannot be prevented.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel supply device for an internal combustion engine, which can maintain the air-fuel ratio optimally and improve exhaust characteristics and acceleration performance during acceleration operation. .

<Means for Solving Problems> Therefore, according to the present invention, as shown in FIG. 1, a predetermined volume chamber is provided in the intake passage between the intake throttle valve of the engine and the engine, and the fuel supply means H is provided. Prepared for the intake port near the combustion chamber,
Fuel for an internal combustion engine including intake air flow rate detection means A for detecting an intake air flow rate upstream of an intake throttle valve of the engine, and fuel supply amount setting means B for setting a fuel supply amount based on the detected intake air flow rate. In the supply device, load detecting means C for detecting an engine load, engine acceleration state detecting means D for detecting an acceleration state of the engine, current engine load detected when the acceleration state of the engine is detected, A load setting means E for setting a new engine load based on the blunting processing coefficient from the previous engine load or the previous engine load subjected to the blunting process, and gradually as the engine load from the start of acceleration increases. Coefficient setting means F for setting the blunting processing coefficient in accordance with the detected engine load or the blunted engine load so that the degree of blunting becomes large.
And a fuel supply amount correcting means G for correcting the set fuel supply amount based on the set new engine load,
Drive control means I for controlling the drive of the fuel supply means H based on the corrected fuel supply amount.

Further, a second blunting processing coefficient is set according to the engine speed so that the degree of blunting gradually decreases as the engine speed increases from the start of acceleration, and the coefficient setting means F is set.
However, the smaller one of the blunting processing coefficient and the second blunting processing coefficient may be selected and set as the blunting processing coefficient.

<Operation> According to this configuration, the coefficient setting means F gradually increases the degree of blunting as the engine load increases from the start of acceleration in accordance with the detected engine load or the blunted engine load. The blunting processing coefficient is set as follows.

That is, when the load is low at the beginning of the acceleration operation, a small value of the blunting processing coefficient is set.

When the acceleration state of the engine is detected, the load setting means E sets a new engine load based on the blunting processing coefficient from the current engine load and the previous engine load, and the fuel supply amount correction means G sets the above-mentioned setting. The fuel supply amount is corrected based on the new engine load.

Therefore, at the time of low load in the initial stage of acceleration operation, the blunting treatment coefficient is small and the blunted engine load is also small. Therefore, a new engine load that is largely dependent on the current load is set. It will be. Therefore, the fuel supply amount correcting means G corrects the fuel supply amount based on the engine load that largely depends on the present load, and the intake air flow rate increases in accordance with the increase in the load for accelerating operation. It is possible to follow up the fuel supply amount with good responsiveness and increase the fuel supply amount.

On the other hand, at the end of the acceleration operation, the load is high and a slightly larger value for the blunting coefficient is set.

Therefore, at the time of high load at the end of acceleration operation, the blunting treatment coefficient is slightly large, and the blunted engine load also becomes large.Therefore, a new engine load that depends on the previous load must be set. Becomes Therefore, the fuel supply amount correcting means G corrects the fuel supply amount based on the engine load that depends on the previous load, and in accordance with the end of the acceleration operation and the end of the increase of the load, that is, the intake air flow rate. It is also possible to suppress the increase in the fuel supply amount in accordance with the end of the increase in the fuel injection amount, and thus it is possible to suppress the overshoot amount.

In other words, it is possible to prevent over-riching at the end of the acceleration operation, and it is possible to always have a constant air-fuel ratio regardless of the load at the end of the acceleration operation.

Next, the second blunting processing coefficient is set according to the engine speed so that the degree of blunting gradually decreases as the engine speed increases from the start of acceleration, and the coefficient setting means F is set.
However, the operation of the case where the smaller one of the blunting processing coefficient and the second blunting processing coefficient is selected and set as the blunting processing coefficient will be described.

In this case, after the engine speed increases due to the acceleration operation, the second blunting treatment coefficient is set so that the degree of blunting gradually decreases as the engine speed increases. The blunting processing coefficient is set as the blunting processing coefficient.

That is, in the medium to high speed rotation range where the amount of overshoot is smaller, the engine load subjected to the blunting process also becomes smaller, so that a new engine load that largely depends on the current load is set. Therefore, the fuel supply amount correction means G corrects the fuel supply amount based on the engine load that largely depends on the current load. Since the intake air flow rate has also finished increasing since the engine speed has increased due to the acceleration operation, the correction is performed with almost no influence of the above-described correction of the fuel supply amount due to the acceleration operation. That is, the fuel supply amount for the current load is set.

Therefore, overriching at the time of acceleration can be prevented, and the air-fuel ratio can always be flattened regardless of the load at the end of the acceleration operation.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 2, the control device 1 including, for example, a microcomputer includes a rotation speed signal output from a rotation speed sensor 2, an intake air flow rate signal output from an air flow meter 3 as an intake air flow rate detecting means, and a water temperature sensor 4.
The cooling water temperature signal output from is input.

The control device 1 operates according to the flowcharts shown in FIGS. 3 and 4, and outputs an injection pulse signal to the fuel injection valve 5 as a fuel supply means via the drive circuit 6. Further, a collector portion as a predetermined volume chamber is provided in an intake passage between the intake throttle valve of the engine and the engine, and the fuel injection valve 5 is provided in an intake port portion near the combustion chamber.

Here, the control device 1 constitutes fuel supply amount setting means, load detecting means, load setting means, coefficient setting means, and fuel supply amount correcting means. Further, the control device 1 and the drive circuit 6 constitute drive control means.

Next, the operation will be described with reference to the flowchart of FIG.
This routine is executed in time synchronization every 10 msec.

In S1, the rotational speed N detected by the sensors, the intake air flow rate Q, reads the various detection such as cooling water temperature T _W.

In S2, the basic injection amount T _P (= K · Q / N; K is a constant) is calculated based on the detected rotation speed N and the intake air flow rate Q.

In S3, the first weighting coefficient X ₁ as the blunting processing coefficient is searched from the map based on the calculated basic injection amount T _P (engine load). As shown in FIG. 4, the first weighting coefficient X ₁ is set to increase as the basic injection amount T _P increases so as to largely depend on the data of the previous routine.

In S4, the second weighting coefficient X ₂ is searched from the map based on the detected engine speed N. As shown in FIG. 5, the second weighting coefficient X ₂ is set so that as the engine speed N increases, the second weighting coefficient X ₂ greatly decreases depending on the data of this routine. This is because the flow rate of intake air taken into the combustion chamber per unit time increases as the rotation speed increases at the same load. Further, the ratio Qc / Qe between the intake air flow rate Qc drawn into the collector portion and the intake air flow rate Qe drawn into the combustion chamber becomes small in the high rotation speed range, and the ratio Qc / Qe becomes large in the low rotation speed range.
Therefore, the second weighting coefficient X2 is set so that it becomes smaller as the rotation speed becomes higher. That is, the second weighting coefficient X2 corresponds to the second blunting processing coefficient described in claim 2.

In S5, the first weighting factor X ₁ is the second weighting factor X ₁ .
_It is determined whether it is ₂ or less, and if YES, the process proceeds to S6
When it is O, the process proceeds to S7.

In S6, the first weighting coefficient X ₁ is set as the weighting coefficient X, while in S7, the second weighting coefficient X ₂ is set as the weighting coefficient. Therefore, the smaller one of the first and second weighting factors X ₁ and X ₂ is selected as the weighting factor X.

In S8, the basic injection amount T _PAVE is calculated by the following weighted average formula based on the set weighting coefficient X and the basic injection amount T _PN calculated this time.

T _PAVE = {T ′ _PAVE (2 ^X −1) + T _PN } / 2 ^X T ′ _PAVE is the weighted average basic injection amount in the previous routine.

In S9, the fuel injection amount T _i is calculated by the following equation based on the newly weighted average basic injection amount T _PAVE .

T _i = T _PAVE × α × COEF + T _S α is an air-fuel ratio feedback correction coefficient, COEF is various correction coefficients mainly for water temperature, and T _S is a correction coefficient based on the battery voltage.

An injection pulse signal corresponding to the fuel injection amount T _i calculated in this manner is output to the fuel injection valve 5 via the drive circuit 6 to perform fuel injection.

As described above, after the weighted average of the basic injection amount based on the first weighting coefficient X ₁ which is set so as to increase the weighted average weighting coefficient as the engine load increases, the fuel injection amount T _i is calculated. Since the calculation is performed, the following effects were obtained during acceleration operation.

That is, since the load (basic injection amount) is small at the initial stage of the acceleration operation and the first weighting coefficient X ₁ is small, the weighted average basic injection amount T _PAVE is the same as the previously calculated basic injection amount T _PN . Depends more heavily on routine data. Therefore, in the initial stage of the acceleration operation, the weighted average basic injection amount T _PAVE rises following the intake throttle valve opening, that is, the rise of the intake air flow rate with good responsiveness, as shown by the broken line in FIG. Therefore, at the initial stage of the acceleration operation, the fuel injection amount corresponding to the actual intake air flow rate sucked into the engine can be supplied to the engine, so that the air-fuel ratio can be optimally controlled, and the acceleration performance and the exhaust characteristic are the same as those of the conventional example. Can be maintained well.

On the other hand, since the load is high and the first weighting coefficient X ₁ is large in the latter period of the acceleration operation, the weighted average basic injection amount T
_PAVE is largely dependent than routine data current to the previous weighted averaged basic injection quantity T _'PAVE. Therefore, in the latter half of the acceleration operation, the weighted average basic injection amount T
_PAVE is suppressed by the previous basic injection amount _T'PAVE , and the increase due to the overshoot can be eliminated as shown by the broken line in FIG. Therefore, in the latter half of accelerated operation,
Even if the intake air flow rate detected by the air flow meter 3 overshoots as shown in FIG. 6, the weighted average basic injection amount T _PAVE does not include that amount. Since the fuel injection amount substantially corresponding to the air flow rate can be supplied to the engine, the air-fuel ratio can be optimally maintained as shown by the broken line in FIG. 6, and thus the CO and HC emission amount can be made wide as shown by the broken line in FIG. It can be suppressed and the acceleration performance can be improved.

Further, the smaller one of the first weighting coefficient X ₁ and the second weighting coefficient X ₂ depending on the rotation speed is selected to perform the weighted average, so that the intake air flow rate detected by the air flow meter 3 is selected. In the high rotation range where the overshoot is small, the weighting average is performed by the second weighting coefficient X ₂ set to be smaller as the rotation becomes higher. For this reason, during the acceleration operation in the medium to high rotation speed range, the basic injection material T _PN of this time largely depends on the acceleration operation, so that the acceleration performance can be greatly improved.

The fuel injection amount may be calculated based on the intake air flow rate detected by the air flow meter 3, and then this amount may be corrected. As the engine load, the basic injection amount T _P , the intake negative pressure, the intake air flow rate, the engine torque, the total opening area between the intake throttle valve and the bypass passage, or the total opening area reduced by the rotational speed, etc. Can be mentioned.

Further, in this embodiment, the fuel injection amount calculation is performed every 10 msec, so the second weighting coefficient X depending on the rotation speed is used.
_{Although 2} is used, when the fuel injection amount calculation is performed in synchronization with the engine speed, the weighting average may be performed only by the first weighting coefficient X ₁ without using the second weighting coefficient X ₂ . In this case, the fuel injection amount may be calculated after performing a weighted average of the intake air flow rate Q detected by the air flow meter 3 (Q = {previous weighted average Q (2 ^X −1) + this time Q} /
2 ^X ).

The weighted average may be calculated by the following formula.

T _AVE = {This time T _P (256-X) + Last weighted average T _AVE · X} / 256 <Effect of the invention> As described above, the present invention largely depends on the previous data as the load increases. Since a new load is set by the blunting processing coefficient to correct the fuel injection amount, while maintaining the acceleration performance in the initial stage of the acceleration operation as good as the conventional example, the intake air flow rate is increased in the latter half of the acceleration operation. Even if the intake air flow rate detected by the detection means overshoots, it is possible to suppress the overshoot, thereby maintaining the air-fuel ratio at an optimum level, and exhaust characteristics,
Acceleration performance and fuel efficiency can be greatly improved.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a configuration diagram showing an embodiment of the present invention, FIG.
FIG. 4 and FIG. 5 are characteristic diagrams of the same as above, and FIG. 6 is a diagram for explaining the conventional defects and the operation of the embodiment. 1 ... Control device, 2 ... Rotational speed sensor, 3 ... Air flow meter, 5 ... Fuel injection valve, 6 ... Drive circuit

Claims (2)

[Claims] 1. An intake air flow rate upstream of an intake throttle valve of an engine, wherein a predetermined volume chamber is provided in an intake passage between the intake throttle valve of the engine and the engine, and fuel supply means is provided in an intake port portion near the combustion chamber. In a fuel supply device for an internal combustion engine, the load detection means for detecting an engine load, the intake air flow rate detection means for detecting an engine load, and the fuel supply amount setting means for setting a fuel supply amount based on the detected intake air flow rate. And the engine acceleration state detection means for detecting the acceleration state of the engine, the current engine load detected when the acceleration state of the engine is detected, the previous engine load or the previous engine load subjected to the blunting process. Therefore, load setting means for setting a new engine load based on the blunting processing coefficient, and the detected engine load so that the degree of blunting gradually increases as the engine load increases from the start of acceleration. Alternatively, a coefficient setting means for setting the blunting processing coefficient according to the engine load subjected to the blunting process, and a fuel supply amount correction for correcting the set fuel supply amount based on the set new engine load A fuel supply device for an internal combustion engine, comprising: a means and a drive control means for driving and controlling the fuel supply means based on the corrected fuel supply amount. 2. A second blunting processing coefficient is set in accordance with the engine speed so that the degree of blunting gradually decreases as the engine speed increases from the start of acceleration. 2. The fuel supply device for an internal combustion engine according to claim 1, wherein a smaller one of the blunting treatment coefficient and the second blunting treatment coefficient is selected and set as a blunting treatment coefficient. .